Storozh, O.G. “Maximal Nonnegative and $\theta$-Accretive Extensions of a Positive Definite Linear Relation: Array”. Carpathian Mathematical Publications 12, no. 2 (October 18, 2020): 289–296. Accessed March 28, 2024. https://journals.pnu.edu.ua/index.php/cmp/article/view/3921.